1. Statement of the Technical Field
The present invention relates to artificial airways and methods therefor, for example, for use in the treatment of respiratory conditions and in assisted respirations, and more particularly for non-sealing gas delivery systems.
2. Description of the Related Art
Artificial airways can be used when a patient requires breathing assistance, or has a deformity or an injury of the airway. Some conventional artificial airways include endotracheal tubes (ET), nasotracheal tubes and tracheotomy tubes. Such artificial airways can be deployed to provide that a patient's airway remains open and to provide access to the lungs for managing or assisting the respiration of the patient. These artificial airways can be used with or without mechanical respiratory ventilation or assistance.
One limitation created by the use of artificial airways is that artificial airways bypass the body's normal upper respiratory tract where inhaled air is warmed and humidified. Exposure of the lower respiratory tract and lungs to dry and or cool air can cause damage to the lower respiratory tract, the lungs and worsen the patient's respiratory condition. The upper respiratory tract also serves as a defense mechanism for the lungs by capturing particles, allergens and pathogens, and preventing their entry into the lower airway.
When a patient is breathing through an artificial airway without the assistance of mechanical ventilation, one standard practice is to supply heated humidity by attaching a Tee fitting to the tube adapter and adding a steady flow of aerosol or heated humidity over the opening of the artificial airway, which is particularly important when delivering oxygen or other anhydrous gas. FIG. 1 illustrates the general format of a convention tee connection 100 for delivery of gas through an artificial airway when a patient is breathing spontaneously. The inlet 102 typically attaches to gas supply (not shown), the artificial airway fitting is typically a 15 mm female fitting, and excess supply gas and exhaled breath from conduit 106 to/from the patient exits to the room through outlet 104.
When the patient inhales using a conventional interface 100 (depending on the inspiratory flow rate and the humidity flow rate) the inhaled gas may be a mixture of room air and therapeutic air/oxygen. Room air may contain particles including pathogens which bypass the normal upper airway. An extension tube may be placed on the exit outflow of the Tee fitting to act as a reservoir for delivered gasses, but this increases the patient's dead air space, and still may not prevent room air from entering the airway. The added dead space may also cause carbon dioxide (CO2) retention, which is undesirable.